Pitch composition



Patented Au 19, 1930 UNITED STATES PATENT orncs CLARENCE a. semi, or ENeLEwooD, EW JERSEY, ASSIGNOR r 'rnn BARRETT COMPANY, or NEW YORK, N. YL, A CORPORATION or NEW JERSEY PITCH COMPOSITION Io Drawing.

This invention relates to a composition of matter and more particularly to a pitch composition especiall adapted for use as a protective coating or surfaces which are a exposed to weatheringsuch as those of'pipe lines, roofs, etc. More specifically, the invention relates to substantially homogeneous mixtures of pitch and filler which have higher melting oints than the corresponding untreated pitches.

One object of this invention is to provide a toughened pitch composition which will not bleed or run at the highest temperatures encountered in use and on the other l hand, will not break or shatter at low temperatures which may be encountered at times. Coal tar and oil tar pitches have heretofore been used for coating and surfacing but present the diificulty that if the meltwin point of the itch is made sufiiciently V high to overcome ow when exposed to maximum summer temperatures, the pitch will be excessively brittle when exposed to'low temperatures, i. 'e. winter temperatures.

According' to the Manhayfer Patent No.

1,112,817 of October 6, 1914 the surfacing and coating properties of pitch are improved by interminglin infusorial earth of kieselguhr therewith 1n such quantities and proportions as to render the finished product plastic. While infusorial earth pitch mixtures represent a substantial improvement over untreated pitch, it has been found that the earth clings together in lumps and it is diflicult to homogeneously disperse it in the pitch, Also, infusorial earth may contain water of hydration which causes foaming when the earthis mixed with hot pitch.

According to my invention, mica is mixed with pitch tow'lplroduce a toughened-pitch composition. infusorial earth, does not cause foaming when mixed with pitch, remains in suspension without an appreciable tendency to settle out, is flaky in structure and has great tensile strength so that when admixed with pitch'it im arts binding strength to the mixture and t us prevents breaking and shattering thereof at low temperatures. A commercial mica readily obtainable on ca is less expensive than Application filed January 23, 1929. Serial No. 334,608.-

the market as such may be used and preferably ground mica of from to 100 mesh is admixed with pitch to form this im roved composition. I have found that satis actor and improved results may be obtained with.

a ground white' mica having the following mesh composition: I

Percent retained on 28 mesh 0.1

Percent passing 28 mesh retained on Y 48 mesh Percent passing 48 mesh. retained on 60 mesh 11.2

Percent passing 60 mesh retained on 7 80 mesh Percent passingv 80 mesh retained ,on

100 mesh 13.0 Percent passing 100 mesh retained on 150 mesh 10.9

Percent passing 150 mesh retained on 200 mesh 6.5 Percent passing 200 mesh 31.8 Loss- 1.0

Total 100.o

The mica of the above mesh composition is known as a No. 80 mica.

By the term pitch as used hereinis meant a residue obtained from the distilla tion of tars andvoils, such as coal tar pitch, and this term includes pitches obtained from coke oven gas and water gas tar, oil tar, pine tar, cannel' tar, asphalt and the like.

The mixture of pitch and mica is preferably prepared by first melting the pitch and then adding from 10 to 30% mica thereto, agitating the pitch while adding the mica and agitating the mixture of pitch and mica preferably by a suitable mechanical agitator or stirred until a substantial homoeneous mixture ofpitch and mica is formed.

t will be noted that the resultant mixture is made by admixing a major proportionoof pitch with a minor proportion of mica, in the particular embodiment disclosed 10% to 30% mica. A pitch of sufliciently high initial melting point to give a. mixture of the the differences itch is of the desired melting point and hen the resultant pitch may be mixed with mica of from 60 to 100 mesh to form the desired'micaitch mixture. I have found that a part ofthe mica may be replaced by as as without deleteriously afiecting the and coating properties of the mix- Preferably, however, mica. is used as sole filler for the pitch. 7 p The following ta ulated properties of micarpitch compositions and infusorial earth pitch compositions invol the same startpitch will serve to indicate the greater e ciency of 'mica in raising the melting po nt pitch": 7 r

' Mdthlg m No. l pitch. 10s I l %mica.. a 15m 4 1]. minimum earth 1N"!A The following "tabulated properties of mica-pitch com 'tion serve to emphasize man mica-pitch composi- It is evident from the foregoing that mica mcorporated in pitchraises the melting. point a considerable extent,'to wit, 62 in the case r of Example 5 involving a I paving pitch' havmg a melting point of 125 p of Example 6; involving a vpitch; 24 inthecaseofExamplei'invol aroo pitch of the melting point of 143 ar'xd'hav I mg 18% mica incorporated therein; 44,'in

' the caseof Example?) involving a water i pitch having a melting point of 165 ,F. and having 20% mica admixed It the case of Example 8 involving a-i-oofing' pitch of 143 F.'melting point and having 21% mica incorporated therein and 15in be noted that the physical of the mica-pitch. composition is dependent upon, the pitch'used and the amount of mica admixed therewith Further, the referred-composition herein consists only of twomgredients, wit,

pitch mica.

g sistmg o a minor; proportion of ground mica The mica-pitch mixtures described herein have'been found articularly valuable as a coating medium or pipe lines-and metals generally, to prevent corrosion and also as a surfacing or coating medium for the purpose of buildmg roofing, particularly for steep built-up roofing where the tendency of the pitch to flow must be slight. This composition may be applied to pipes or metals by dipping the pipes or metalsinto a bath containmg the mica-pitch mixture or by wiping the mica-pitch composition'onto the material or. article to be coated or by any other suitable means slich as s raying and the like.

The property of e mica pitch. mixture to become freely fluid at elevated temperatures, i. e.,- at temperatures somewhat above the meltin point of the mica pitch mixture, renders t e mixture as hereinabove indicated particularly -or metals suitable for application to pipes y pp p P spraying processes. The mica pitch composition at temperatures below the melting point is substantiall solid butuponibeing heated to somewhat a ove the melting point becomes freely fluid, forming a liquid whichis sub- I stantially which I have found isadmirably suited for purposes of coating or enameling metal.

The melting point of the mica pitch mix- 7 ture may be determined by any of the known methods but preferably is'determined by the ring and ball method, AS T M standard method D-36-26. H

While preferred embodiments of this invention have been described, it willlbe underhomogeneous throughout and stood that this-invention is not-to be limited by the disclosure herein but only: by the scope of the appended claims,

Iclaim: l. A mica pitch "composition "having a melting point higher than the pitch and comprising a major proportion of pitch and a minor proportion of mica'substantially ho mogeneously admixedwith the pitch, the composition being freely fluid atrtemperaturessomewhat above its melting point.

2. -A mie'a pitch composition having a melting point higher than the pitch and comprlsing a ma or proportion of coal tar pitch and a minor report-ion of mica, the mica bethroughout the p'itch.

3. A pitch composition having a int higher than thepitch and conmg .subsmnaauy; homogeneously admixed substantially homogeneously admixed with a major proportion of pitch, the composition containing inthe neighborhood of at least 10% mica.

'- 4; A-micapi h m osiatn having a melting point higher than the pitchand consistmg of a minor proportion of. ground" mica substantially homogen'ec'usly admixed with a ma or proportion of tarpitch.

5. A mica pitch composition having a melting point higher than the itch and comprising at least approximate y 10% mica substantially homogeneously admixed with a major proportion of pitch which has'a melting point above approximately 125 F.

6. A mica pitch composition having a melting point higher than the pitch and comprising in the neighborhood of at. least 10% ground mica substantially homogeneously admixed with coal tar pitch which has a melting oint above approximately 125 F.

7. A mica pitch composition having a melting point higher than the pitch and comprising in the neighborhood of at least 10% ground mica of below 100 mesh substantially homogeneously admixed with coal tar pitc which has a melting point above approximatelX 125 F.

8. mica pitch composition having a melting point higher than the pitch and comprising from 10 to 30% of ground mica sub-' stantially homogeneously admixed with pitch.

9; A mica pitch composition having a melting point higher than the pitch and consisting of from 10 to 30% of ground mica substantially homogeneously admixed with pitch.

prising stantially homogeneously admixed with coal 0 tar pitch which has a melting point above approximately. 125 F. v

11. A composition of matter consisting of I approximately 20% of ground mica and c'o'al tar pitch substantially homogeneously admixed therewith. V

12-. A com osition of matter consisting of approximate y 20% of ground mica of from to mesh and coal tar pitch which has a melting point of approximately F. submy hand.

stantially homogeneously admixed therewith.

13. A composition .of matter suitable for.

coating conslsting of approximately 20% mica of approximately 80 mesh substantially homogeneously admixed with 80% of coal tar pitch of approximately 140 F. melting point. i

1 In testimony whereof I have hereunto set CLARENCE R.

A mica pitch composition having a melting point higher than the pitch and comrom 10 to 30% of ground mica sub- 

